At least three printings of this exist. The 3rd printing is clearly labeled in the indicia and has only the US price on the cover (no UK or Canadian prices). The third printing also has the CCA stamp which is not on the 1st printing's cover.
This art was done by Herb Trimpe, and not by Mark Bright, the artist commonly credited for the published cover. This means the Megatron on the original cover art for this issue is a photostat.